Nitrogen-Doped Graphene Supported Cobalt Oxide for Sensitive Determination of Dopamine in Presence of High Level Ascorbic Acid

Abstract

In this report, nitrogen-doped reduced graphene oxide supported cobalt in mixed-oxide (NrGO-Co3O4) has been prepared by simple hydrothermal method and applied as an electrocatalyst for the selective determination of dopamine (DA) over in various biointerfering molecules. Various instrumental analyses have confirmed that the NrGO-Co3O4 nanocomposite has prepared successfully. The detection of DA at as prepared NrGO-Co3O4 has verified through various electrochemical techniques in a 0.1 M phosphate buffer solution (PBS) at pH 7.4. No significant interference has observed in presence of several electroactive interferences; especially, 1000 magnitude higher concentration of AA has shown insignificant interference in the DA detection on NrGO-Co3O4. Overall analytical performance demonstrates a good DA sensing at NrGO-Co3O4 with better sensitivity (369 μA mM−1 cm−2), long detection range (0.3−800.8 μM) and lower detection limit (0.029 μM). The catalytic rate constant and diffusion coefficient for DA detection has been calculated as 6.6 × 104 M−1 s−1 and 5.05 × 10−6 cm2 s−1, respectively. This proposed electrocatalyst has finally shown very satisfactory result on real urine sample analysis.